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Allocate 32 bit memory on OSX/x64 with mmap() hinting.

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Must set -pagezero_size, otherwise the lower 4GB are blocked.
This commit is contained in:
Mike Pall 2010-03-04 16:27:42 +01:00
parent 3d2abf3148
commit f76e5a311b
2 changed files with 43 additions and 5 deletions
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3
src/Makefile
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@ -227,6 +227,9 @@ ifeq (Darwin,$(TARGET_SYS))
TARGET_DYNXLDOPTS=
TARGET_XSHLDFLAGS+= -install_name $(PREFIX)/lib/$(TARGET_DYLIBNAME)
endif
ifeq (x64,$(TARGET_CCARCH))
TARGET_XLDFLAGS+= -pagezero_size 10000 -image_base 100000000
endif
else
TARGET_XLDFLAGS+= -Wl,-E
ifeq (Linux,$(TARGET_SYS))

45
src/lj_alloc.c
View File

@ -164,23 +164,58 @@ static LJ_AINLINE int CALL_MUNMAP(void *ptr, size_t size)
#define MMAP_FLAGS (MAP_PRIVATE|MAP_ANONYMOUS)
#if LJ_64
/* Need special support for allocating memory in the lower 2GB. */
/* 64 bit mode needs special support for allocating memory in the lower 2GB. */
#if defined(__linux__)
/* Actually this only gives us max. 1GB in current Linux kernels. */
#define CALL_MMAP(s) mmap(0, (s), MMAP_PROT, MAP_32BIT|MMAP_FLAGS, -1, 0)
#define CALL_MMAP(s) mmap(NULL, (s), MMAP_PROT, MAP_32BIT|MMAP_FLAGS, -1, 0)
#elif defined(__MACH__) && defined(__APPLE__)
#error "NYI: no support for 64 bit OSX (yet)"
/* OSX mmap() uses a naive first-fit linear search. That's perfect for us.
** But -pagezero_size must be set, otherwise the lower 4GB are blocked.
*/
#define MMAP_REGION_START ((uintptr_t)0x10000)
#define MMAP_REGION_END ((uintptr_t)0x80000000)
static LJ_AINLINE void *CALL_MMAP(size_t size)
{
/* Hint for next allocation. Doesn't need to be thread-safe. */
static uintptr_t alloc_hint = MMAP_REGION_START;
int retry = 0;
for (;;) {
void *p = mmap((void *)alloc_hint, size, MMAP_PROT, MMAP_FLAGS, -1, 0);
if ((uintptr_t)p >= MMAP_REGION_START &&
(uintptr_t)p + size < MMAP_REGION_END) {
alloc_hint = (uintptr_t)p + size;
return p;
}
if (p != CMFAIL) munmap(p, size);
if (retry) break;
retry = 1;
alloc_hint = MMAP_REGION_START;
}
return CMFAIL;
}
#elif defined(__FreeBSD__) || defined(__FreeBSD_kernel__)
/* FreeBSD 64 bit kernel ignores mmap() hints for lower 32GB of memory. */
/* See /usr/src/sys/vm/vm_mmap.c near RLIMIT_DATA. */
/* See: grep -C15 RLIMIT_DATA /usr/src/sys/vm/vm_mmap.c */
#error "No support for 64 bit FreeBSD"
#else
#error "NYI: need an equivalent of MAP_32BIT for this 64 bit OS"
#endif
#else
#define CALL_MMAP(s) mmap(0, (s), MMAP_PROT, MMAP_FLAGS, -1, 0)
/* 32 bit mode is easy. */
#define CALL_MMAP(s) mmap(NULL, (s), MMAP_PROT, MMAP_FLAGS, -1, 0)
#endif
#define INIT_MMAP() ((void)0)